Major loss of salivary gland acinar and other epithelial cells to disease or radiation therapy results in severe curtailment of saliva, causing marked oral discomfort and disease and loss of teeth. The long range objective is to find ways to regenerate gland structures to relieve these problems. Using the rat submandibular gland as a model, we propose to move towards this objective via three approaches. (1) Determine which of the several types of salivary gland cells have the potential to proliferate and redifferentiate into the acini and ducts required to restore gland function. (2) Develop methods to deliver these cells into salivary glands and foster their development into new acini and ducts. (3) Develop conditions for inducing hematopoietic stem cells to differentiate into salivary gland cells in vitro and in vivo, thus providing the potential for an autologous, non-glandular source of cells for delivery into damaged glands. Previously developed primary culture conditions will be refined to produce nearly pure acinar, intercalated duct and larger duct cells, then switched to learn to what extent the cells can re-differentiate in vitro. Dispersed salivary acinar or ductal cells from male rats will be seeded into salivary glands of female rats by infusion into the main duct with enough pressure to leak into the stroma, or by injection into the gland, and followed via their Y chromosomes for proliferation and differentiation in situ. Hematopoetic stem cells from male rats will be collected and tested for salivary differentiation in co-culture with female salivary gland cells or seeded in situ as above, also using the Y chromosome to mark stem cells and their progeny.